Re: Compiling 2.6 kernel questions

[Glynn Clements <glynn@gclements.plus.com>]

Alex wrote:

> I'm trying to compile 2.6.32-pre8 and have some questions that I hoped
> someone could help me to answer. They aren't really specific to the
> kernel version, other than I'm using 2.6.
> 
> - Is it possible to compile a kernel with glibc-2.10.1 and run it on a
> system with a much older glibc version? Specifically, I'd like to
> upgrade a v2.4 kernel system to v2.6 with only the minimal amount of
> changes in order for it to run.

The version of glibc installed on the build system has no effect upon
the resulting kernel.

glibc tends to be quite independent of the kernel version. For the
most part, you can still run binaries linked against libc.so.5 on a
2.6 kernel.

> - Is it necessary to compile the IDE driver and ext2/3 filesystem
> driver into the kernel, or can that also be a module?

If you build either as a module, you need to use initrd or initramfs. 

> If so, and I put
> it in initrd,. how is it accessed? Isn't it a catch-22 without having
> support to access the very ramdisk that has the support that's
> necessary to access it?

To use initrd, the device driver and file system have to be built into
the kernel. 2.6 kernels support initramfs, which doesn't require a
separate device driver or filesystem module (the code is always built
into the kernel). See Documentation/filesystems/ramfs-rootfs-initramfs.txt
for details.

> If this can be done, where can I find info on the steps?

Unless you're particularly short for space, start by building a kernel
with IDE and ext2 built in, and deal with initrd/initramfs later.

> - Is there a general list of minimum requirements for compiling a
> recent 2.6 kernel? IOW,  module-init-tools, gcc, etc.

The file Documentation/Changes in the kernel source tree lists minimum
versions.

> - Does anyone use lilo anymore, or do all distros use grub?

Gentoo offers a choice of boot loaders; I use lilo.

-- 
Glynn Clements <glynn@gclements.plus.com>